Objective:

The determination of pollutants in seawater
is an area that has not been well studied in environmental sciences. There
is a need to know
the levels of endocrine disrupting chemicals (EDCs) in the coasts of Puerto
Rico because of the continuous release of sewage effluents with primary treatment.
The objective of this research project is to develop and validate a methodology
to study EDCs in seawater.

Approach:

Solid phase microextraction (SPME) is being used
as the extraction technique and gas chromatography/mass spectrometry for
the chemical analysis.
A polydimethylsiloxane/divinylbenzene 65µm fiber was better for the
extraction of the EDCs standards studied from the model matrix in comparison
with other
fiber coatings. An extraction time of 45 minutes was determined from the
extraction time profiles as well as practical limitations. Sample stirring
was observed
as an important parameter in SPME, in which 700 rpm was chosen in our research
project. A 20-mL sample volume was chosen because of a marked increase in
the extraction efficiency for most of the model compounds. Sample pH and
glassware
deactivation also were studied in this methodology. A decrease in extraction
efficiency was observed when commercial humic substances were added to the
model matrix. Natural humic material has been sampled from seawater at the
coast of Cabo Rojo (El Faro) because this material is not commercially available
and its properties are unique of the source of the material. Fourier transform
infrared spectroscopy, H1 nuclear magnetic resonance spectroscopy, and ultraviolet
infrared spectroscopy were acquired for the isolated fulvic and humic material.
Also, an elemental analysis for some specific elements was performed. The
effect of multiple samplings on the fiber was studied using scanning electron
microscopy.
A temperature effect will be studied in this methodology. Real samples will
be taken and analyzed using the developed methodology.

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.